Optical fibers are useful in a wide variety of applications, including the telecommunications industry for voice, video, and data transmissions. The benefits of optical fiber are well known and include higher signal-to-noise ratios and increased bandwidth compared to conventional copper-based transmission technologies. To meet modern demands for increased bandwidth and improved performance, telecommunication networks are increasingly providing optical fiber connectivity closer to end subscribers. These initiatives include fiber-to-the-node (FTTN), fiber-to-the-premises (FTTP), fiber-to-the-home (FTTH), and the like (generally described as FTTx).
In an FTTx network, fiber optic cables are used to carry optical signals to various distribution points and, in some cases, all the way to end subscribers. For example, FIG. 1 is a schematic diagram of an exemplary FTTx network 10 that distributes optical signals generated at a switching point 12 (e.g., a central office of a network provider) to subscriber premises 14. Optical line terminals (OLTs; not shown) at the switching point 12 convert electrical signals to optical signals. Fiber optic feeder cables 16 then carry the optical signals to various local convergence points 18, which act as locations for splicing and making cross-connections and interconnections. The local convergence points 18 often include splitters to enable any given optical fiber in the fiber optic feeder cable 16 to serve multiple subscriber premises 14. As a result, the optical signals are “branched out” from the optical fibers of the fiber optic feeder cables 16 to optical fibers of distribution cables 20 that exit the local convergence points 18.
At network access points closer to the subscriber premises 14, some or all of the optical fibers in the distribution cables 20 may be accessed to connect to one or more subscriber premises 14. Drop cables 22 extend from the network access points to the subscriber premises 14, which may be single-dwelling units (SDU), multi-dwelling units (MDU), businesses, and/or other facilities or buildings. A conversion of optical signals back to electrical signals may occur at the network access points or at the subscriber premises 14.
There are many different network architectures, and the various tasks required to distribute optical signals (e.g., splitting, splicing, routing, connecting subscribers) can occur at several locations. Regardless of whether a location is considered a local convergence point, network access point, subscriber premise, or something else, fiber optic equipment is used to house components that carry out one or more of the tasks. The term “terminal” will be used in this disclosure to generically refer to such equipment, which may include fiber distribution hubs (FDH), cabinets, closures, network interface devices, etc. In many current network architectures, terminals at local convergence points 18 are configured to split the signal in each of the optical fibers carried in the feeder cable 16 (referred to as feeder optical fibers for terminal 30). The feeder optical fibers of the feeder cable 16 are routed to one or more splitter modules carried in the terminal 30 where the optical signal in the feeder optical fibers is split between a plurality of output fibers. By way of example, the splitter module may be configured to split the incoming optical signal between 2 and 32 times. The output fibers of the splitter module are then coupled to a dedicated distribution cable 20 in the terminal 30 for distribution to subscriber premises 14. The optical signal carried by any one of the distribution cables 20 is a split version of the optical signal carried by an optical fiber of the feeder cable 16.
While current network architectures with terminals 30 as described above adequately meet current demands for end subscribers, service providers continually seek improved network architectures that provide greater flexibility in the optical fiber network. As the demand for bandwidth from end subscribers continues to increase, the ability to provide a terminal (such as at a local convergence point 18) capable of servicing all the different types of end subscribers (e.g., homes, apartments, business, etc.) from that terminal may become increasingly difficult. For example, the ability for current terminals to serve both a residential neighborhood and a large office complex may not be feasible as demand increases. This may be due in part to the fact that current terminal designs are configured to split the optical signal from each of the optical fibers of the feeder cable 16. Thus, the output optical signals carried by the distribution cables 20 are attenuated or modified compared to the more powerful optical signals carried by the feeder cable 16, and this may limit the ability of the terminal to service the different types of end subscribers in the vicinity of the terminal.